Mold and Mildew Growth

Mold and mildew growth is clearly visible on these floor joists. This is a symptom of the crawl space being unsealed and unprotected from outside air and moisture. When there are warmer temperatures and the relative humidity reaches at least 60%, mold and mildew can start to form on any organic materials within the crawl space. The musty odors and mold spores rising from the crawl space into the living space above can irritate those with asthma and allergies.